D-Link DGS-2208 User Manual page 10

Section 2 - Product Overview
Switches provide full-line speed and dedicated bandwidth for all connections. This is in contrast to hubs, which use
the traditional shared networking topology, where the connected nodes contend for the same network bandwidth.
When two switching nodes are communicating, they are connected with a dedicated channel between them, so there
is no contention for network bandwidth with other nodes. As a result, the switch reduces considerably, the likelihood
of traffic congestion.
For Ethernet networks, a switch is an effective way of eliminating the problem of chaining hubs beyond the "two-repeater
limit." A switch can be used to split parts of the network into different collision domains, making it possible to expand
your Ethernet network beyond the 205-meter network diameter limit for 100BASE-TX networks. Switches supporting
both 10Mbps Ethernet and 100Mbps Fast Ethernet are also ideal for bridging between existing 10Mbps networks and
newer 100Mbps networks.
Switching LAN technology is a marked improvement over the previous generation of network hubs and bridges, which
were characterized by higher latencies. Routers have also been used to segment local area networks, but the cost of
a router, the setup and maintenance required, make routers relatively impractical. Today switches are an ideal solution
to most kinds of local area network congestion problems.
802.1p Priority Tagging
802.1p places a tag in a frame to indicate the priority of the frame. A tag will represent a priority of 0-7 and an 802.1p
compliant switch can read this tag and prioritize traffic accordingly. In 802.1p a port can receive frames with varying
priority tags and classify them based on these tags. A VoIP phone that supports 802.1p can assign a priority to its
VoIP traffic and when it enters the switch the switch can give it a higher priority so that voice traffic is always clear and
jitter free. The DGS-2208 supports the 802.1p feature with 4 preconfigured priority queues. When a frame tagged with
an 802.1p priority bit is received by the switch it places the frame into one of 4 queues prioritized according to its tag
number. For example, traffic tagged with a priority bit of 7 will have a higher priority then traffic tagged with a priority
bit of 6 and so forth.
Jumbo Frame Support
The DGS-2208 switch supports Jumbo Frames up to (9720 Bytes) in size. Jumbo Frame support is designed to improve
network throughput and significantly reduce the CPU utilization of large file transfers such as multimedia files or large
data files by enabling more efficient larger payloads per packet.
D-Link DGS-2208 User Manual 10